Index: head/lib/libzstd/Makefile
===================================================================
--- head/lib/libzstd/Makefile	(revision 331114)
+++ head/lib/libzstd/Makefile	(revision 331115)
@@ -1,46 +1,53 @@
 # $FreeBSD$
 
 LIB=	zstd
 SRCS=	entropy_common.c \
 	error_private.c \
 	fse_decompress.c \
 	pool.c \
 	threading.c \
 	xxhash.c \
 	zstd_common.c \
 	fse_compress.c \
 	huf_compress.c \
 	zstd_compress.c \
 	zstdmt_compress.c \
 	huf_decompress.c \
 	zstd_decompress.c \
 	zbuff_common.c \
 	zbuff_compress.c \
 	zbuff_decompress.c \
 	cover.c \
 	divsufsort.c \
 	zdict.c \
 	zstd_fast.c \
 	zstd_lazy.c \
 	zstd_ldm.c \
 	zstd_opt.c \
 	zstd_double_fast.c
 WARNS=	2
 INCS=	zstd.h
 CFLAGS+=	-I${ZSTDDIR}/lib -I${ZSTDDIR}/lib/common -DXXH_NAMESPACE=ZSTD_ \
 		-DZSTD_MULTITHREAD=1
 LIBADD=	pthread
 
 PRIVATELIB=	yes
 
 ZSTDDIR=	${SRCTOP}/sys/contrib/zstd
 .PATH:	${ZSTDDIR}/lib/common ${ZSTDDIR}/lib/compress \
 	${ZSTDDIR}/lib/decompress ${ZSTDDIR}/lib/deprecated \
 	${ZSTDDIR}/lib/dictBuilder ${ZSTDDIR}/lib
 
 # Work around for LLVM bug 35023, https://bugs.llvm.org/show_bug.cgi?id=35023
 .if ${MACHINE_ARCH:Marm*} != ""
 CFLAGS.zstd_compress.c+= -O0
 .endif
 
+# Work around lack of __bswap[sd]i2() intrinsics on riscv.  Probably should be
+# added to one of the runtime C libraries instead.
+.if ${MACHINE_CPUARCH} == "riscv"
+.PATH:	${ZSTDDIR}/lib/freebsd
+SRCS+=	zstd_kfreebsd.c
+.endif
+
 .include <bsd.lib.mk>
Index: head/sys/contrib/zstd/lib/freebsd/zstd_kfreebsd.c
===================================================================
--- head/sys/contrib/zstd/lib/freebsd/zstd_kfreebsd.c	(revision 331114)
+++ head/sys/contrib/zstd/lib/freebsd/zstd_kfreebsd.c	(revision 331115)
@@ -1,89 +1,94 @@
 /*-
  * Copyright (c) 2018 Conrad Meyer <cem@freebsd.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  * $FreeBSD$
  */
 
 #include "zstd_kfreebsd.h"
+#include <sys/param.h>
 #include <sys/endian.h>
+
+#ifndef _KERNEL
+#include <strings.h>
+#endif
 
 /*
  * The kernel as a standalone target does not link against libgcc or
  * libcompiler-rt. On platforms (e.g., MIPS and RISCV) that do not have a
  * direct assembly implementation of the relevant builtin functions that zstd
  * references, the compiler converts them into calls to the runtime library
  * intrinsics.  Since the kernel does not link against the runtime libraries,
  * this results in a failure to link the kernel.
  *
  * The goal of the following definitions is to use supported kernel constructs
  * to implement the same functionality, without adding diff to the Zstd contrib
  * code.
  *
  * A subsequent enhancement might create a mini compiler-rt library for kernel
  * use and move these over there instead.
  */
 
 /* Swap endianness */
 int
 __bswapsi2(int x)
 {
 	return (bswap32(x));
 }
 
 long long
 __bswapdi2(long long x)
 {
 	return (bswap64(x));
 }
 
 /* Count trailing zeros */
 int
 __ctzsi2(int x)
 {
        if (x == 0)
                return (sizeof(x) * NBBY);
        return (ffs(x) - 1);
 }
 
 long long
 __ctzdi2(long long x)
 {
        if (x == 0)
                return (sizeof(x) * NBBY);
        return (ffsll(x) - 1);
 }
 
 /* Count leading zeros */
 int
 __clzsi2(int x)
 {
        return (sizeof(x) * NBBY - fls(x));
 }
 
 long long
 __clzdi2(long long x)
 {
        return (sizeof(x) * NBBY - flsll(x));
 }